U.S. patent application number 16/453861 was filed with the patent office on 2019-12-26 for method of controlling liquid ejecting apparatus and liquid ejecting apparatus.
The applicant listed for this patent is SEIKO EPSON CORPORATION. Invention is credited to Tomoshige KANEKO, Hiroaki OKUI.
Application Number | 20190389201 16/453861 |
Document ID | / |
Family ID | 68980459 |
Filed Date | 2019-12-26 |
![](/patent/app/20190389201/US20190389201A1-20191226-D00000.png)
![](/patent/app/20190389201/US20190389201A1-20191226-D00001.png)
![](/patent/app/20190389201/US20190389201A1-20191226-D00002.png)
![](/patent/app/20190389201/US20190389201A1-20191226-D00003.png)
![](/patent/app/20190389201/US20190389201A1-20191226-D00004.png)
![](/patent/app/20190389201/US20190389201A1-20191226-D00005.png)
![](/patent/app/20190389201/US20190389201A1-20191226-D00006.png)
![](/patent/app/20190389201/US20190389201A1-20191226-D00007.png)
![](/patent/app/20190389201/US20190389201A1-20191226-D00008.png)
![](/patent/app/20190389201/US20190389201A1-20191226-D00009.png)
![](/patent/app/20190389201/US20190389201A1-20191226-D00010.png)
United States Patent
Application |
20190389201 |
Kind Code |
A1 |
KANEKO; Tomoshige ; et
al. |
December 26, 2019 |
METHOD OF CONTROLLING LIQUID EJECTING APPARATUS AND LIQUID EJECTING
APPARATUS
Abstract
A method of controlling a liquid ejecting apparatus that
includes a liquid ejecting head having nozzles configured to eject
a liquid, pressure chambers communicating with the nozzles, and
drive elements configured to change the volume in the pressure
chambers, and a drive-waveform generating circuit configured to
generate a drive waveform for driving the drive elements to vibrate
the liquid in the nozzles is provided. The method includes
detecting a power-off operation for issuing an instruction for
turning off an electric power of the liquid ejecting apparatus and
vibrating the liquid by driving piezoelectric elements by the drive
waveform in response to detecting the power-off operation by the
detecting.
Inventors: |
KANEKO; Tomoshige;
(Kamiina-Gun Minamiminowa-Mura, JP) ; OKUI; Hiroaki;
(Azumino-Shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEIKO EPSON CORPORATION |
Tokyo |
|
JP |
|
|
Family ID: |
68980459 |
Appl. No.: |
16/453861 |
Filed: |
June 26, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B41J 2/04581 20130101;
B41J 2/0457 20130101; B41J 2/04588 20130101; B41J 2/04553 20130101;
B41J 2/04596 20130101; B41J 2/04563 20130101; B41J 2/16517
20130101 |
International
Class: |
B41J 2/045 20060101
B41J002/045 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 26, 2018 |
JP |
2018120535 |
Claims
1. A method of controlling a liquid ejecting apparatus that
includes a liquid ejecting head having nozzles configured to eject
a liquid and drive elements configured to generate pressure
fluctuations in liquid chambers communicating with the nozzles, the
method comprising: detecting a power-off operation for issuing an
instruction for turning off an electric power of the liquid
ejecting apparatus; and driving the drive elements to the extent
the liquid is not ejected from the nozzles in response to detecting
the power-off operation by the detecting.
2. The method of controlling the liquid ejecting apparatus
according to claim 1, wherein after the driving, performing the
power-off operation without ejecting or discharging the liquid from
the nozzles.
3. The method of controlling the liquid ejecting apparatus
according to claim 1, wherein performing the driving without
sealing openings of the nozzles, and after the driving, sealing the
openings of the nozzles, and performing the power-off
operation.
4. The method of controlling the liquid ejecting apparatus
according to claim 1, wherein in response to detecting the
power-off operation by the detecting, acquiring temperature
information on an environment in which the liquid ejecting
apparatus is installed; and determining whether to perform or not
to perform the driving based on the acquired temperature
information.
5. The method of controlling the liquid ejecting apparatus
according to claim 1, wherein in response to detecting the
power-off operation by the detecting, requesting a user to input
environment information on an environment in which the liquid
ejecting apparatus is installed; and determining whether to perform
or not to perform the driving based on the environment information
input by the user.
6. A method of controlling a liquid ejecting apparatus that
includes a liquid ejecting head having nozzles configured to eject
a liquid and drive elements configured to generate pressure
fluctuations in liquid chambers communicating with the nozzles, the
method comprising: driving the drive elements to the extent that
the liquid is not ejected from the nozzles; and after the driving,
performing a power-off operation to the liquid ejecting apparatus
without ejecting or discharging the liquid from the nozzles.
7. The method of controlling the liquid ejecting apparatus
according to claim 1, wherein after the power-off operation, when a
power-on operation for issuing an instruction for turning on the
electric power is detected, in a case in which the driving has been
performed and then the power-off operation has been performed,
forcibly discharging the liquid from the nozzles, and in a case in
which the power-off operation has been performed without the
driving, not forcibly discharging the liquid from the nozzles.
8. A liquid ejecting apparatus comprising: a liquid ejecting head
having nozzles configured to eject a liquid and drive elements
configured to generate pressure fluctuations in liquid chambers
communicating with the nozzles, wherein the drive elements are
driven to the extent that the liquid is not ejected from the
nozzles in response to detection of a power-off operation for
issuing an instruction for turning off an electric power of the
liquid ejecting apparatus.
9. A liquid ejecting apparatus comprising: a liquid ejecting head
having nozzles configured to eject a liquid and drive elements
configured to generate pressure fluctuations in liquid chambers
communicating with the nozzles, wherein after the drive elements
have been driven to the extent that the liquid is not ejected from
the nozzles, an electric power is turned off without ejection or
discharge of the liquid from the nozzles.
Description
[0001] The present application is based on, and claims priority
from JP Application Serial Number 2018-120535, filed Jun. 26, 2018,
the disclosure of which is hereby incorporated by reference herein
in its entirety.
BACKGROUND
1. Technical Field
[0002] The present disclosure relates to a method of controlling a
liquid ejecting apparatus capable of reducing damage to components
caused by freeze of liquid in a liquid flow path and a liquid
ejecting apparatus.
2. Related Art
[0003] Liquid ejecting apparatuses have a liquid ejecting head and
eject (discharge) various kinds of liquids from the liquid ejecting
head. Examples of the liquid ejecting apparatuses include image
recording apparatuses such as ink jet printers and ink jet
plotters. In recent years, the liquid ejecting apparatuses have
been applied to various manufacturing apparatuses by taking
advantage of the ability to accurately eject a very small amount of
liquid to predetermined positions. For example, the liquid ejecting
apparatuses are applied to display-manufacturing apparatuses for
manufacturing color filters for liquid crystal displays and the
like, electrode-forming apparatuses for forming electrodes for
organic electro luminescence (EL) displays, field emission displays
(FEDs), and the like, and chip-manufacturing apparatuses for
manufacturing biochips (biochemical elements). Recording heads for
image recording apparatuses eject liquid inks, and color material
ejecting heads for manufacturing displays eject solutions of
coloring materials of red (R), green (G), and blue (B).
Electrode-material ejection heads for electrode-forming apparatuses
eject liquid electrode materials, and bioorganic-compound ejecting
heads for chip-manufacturing apparatuses eject solutions of
bioorganic compounds.
[0004] Such a liquid ejecting head has a liquid path that extends
from a common liquid chamber (may be referred to as a reservoir or
a manifold) through a pressure chamber (may be referred to as a
pressure generating chamber or a cavity) to a nozzle. The liquid
ejecting head generates pressure fluctuations in the liquid in the
pressure chamber by driving an actuator such as a piezoelectric
element and ejects the liquid from the nozzle as droplets by the
pressure fluctuations. In a general liquid ejecting apparatus
having a liquid ejecting head, depending on the installation
environment, the liquid in internal flow path in the liquid
ejecting head may freeze. The frozen liquid in the liquid path may
cause breakage of the components of the liquid ejecting head due to
the volume expansion by freeze. Cracks are likely to be produced,
in particular, in walls that define high-density pressure chambers.
To solve the problem, there has been proposed a structure for
discharging a liquid from a component, such as the above-described
pressure chamber, that may be broken due to freeze in an
environment in which there is a possibility of liquid freeze (for
example, see JP-A-2009-061779).
[0005] The structure in which the liquid is moved and discharged
from the component that may be broken due to freeze, however,
requires a component such as a pump for increasing or reducing the
pressure in the liquid flow path to move the liquid, resulting in
an increase in size and complexity of the apparatus. Furthermore,
such a structure replaces the liquid in the liquid flow path with
air, and thus air bubbles tend to mix with the liquid when the
liquid flow path is refilled with the liquid. These air bubbles may
cause a failure such as poor liquid ejection from the nozzle.
SUMMARY
[0006] The present disclosure is directed to a method of
controlling a liquid ejecting apparatus capable of reducing damage
to components caused by freeze of liquid in a liquid flow path and
a liquid ejecting apparatus.
[0007] According to an aspect of the present disclosure, a method
of controlling a liquid ejecting apparatus that includes a liquid
ejecting head having nozzles configured to eject a liquid and drive
elements configured to generate pressure fluctuations in liquid
chambers communicating with the nozzles is provided. The method
includes detecting a power-off operation for issuing an instruction
for turning off an electric power of the liquid ejecting apparatus
and driving the drive elements to the extent the liquid is not
ejected from the nozzles in response to detecting the power-off
operation by the detecting.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a front view of a structure of a liquid ejecting
apparatus according to an embodiment.
[0009] FIG. 2 is a block diagram illustrating an electric
configuration of a liquid ejecting apparatus.
[0010] FIG. 3 is a cross-sectional view of a liquid ejecting
head.
[0011] FIG. 4 illustrates example waveforms of print drive
signals.
[0012] FIG. 5 illustrates an example waveform of a micro-vibration
drive pulse.
[0013] FIG. 6 illustrates an example waveform of a
vibration-operation drive signal.
[0014] FIG. 7 illustrates an example waveform of an evaporation
micro-vibration drive pulse.
[0015] FIG. 8 is a flowchart illustrating a method of controlling a
printer relating to an evaporation micro-vibration operation.
[0016] FIG. 9 is a flowchart illustrating processing to be
performed when an electric power supply is turned on after an
evaporation micro-vibration operation and power shutdown of the
printer.
[0017] FIG. 10 is a flowchart illustrating a method of controlling
a printer relating to an evaporation micro-vibration operation
according to a second embodiment.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0018] Hereinafter, embodiments of the disclosure will be described
with reference to the attached drawings. Although the following
embodiments describe various limitations as preferred embodiments
of the disclosure, it is to be understood that the scope of the
disclosure is not limited to the embodiments unless otherwise
specifically described to limit the disclosure in the following
description. In the following description, as an example liquid
ejecting apparatus according to embodiments of the disclosure, an
ink jet recording apparatus (hereinafter, referred to as a printer)
will be described.
[0019] FIG. 1 is a front view of a structure of a printer 1
according to an embodiment, the printer 1 including a recording
head 10 that is a liquid ejecting head. FIG. 2 is a block diagram
illustrating an electric configuration of the printer 1. The
printer 1 includes a frame 2 and a platen 3 that is provided in the
frame 2. A print medium such as a recording sheet, a cloth, or a
resin sheet is transported on the platen 3 by a print-medium
transport mechanism 4 (see FIG. 2). In the frame 2, a guide rod 5
is provided in parallel with the platen 3. The guide rod 5 slidably
supports a carriage 6 on which the recording head 10 is mounted.
The carriage 6 reciprocates along the guide rod 5 in main scanning
directions that are orthogonal to a transport direction of a print
medium with a driving force from a carriage-moving mechanism 7 (see
FIG. 2). While the printer 1 reciprocating the carriage 6 along the
main scanning axis with respect to a print medium mounted on the
platen 3, the printer 1 ejects an ink (a liquid according to the
embodiment) from nozzles 30 (see FIG. 3) of the recording head 10
to form (record or print) an impact pattern such as texts or images
with dot arrays formed by the ink ejected onto the print
medium.
[0020] To the cartridge 6, an ink cartridge 8 that stores an ink is
detachably attached. Example inks include inks having various known
compositions, for example, a water-based dye ink, a water-based
pigment ink, an organic solvent-based (eco-solvent-based) ink
having weather resistance higher than that of the water-based inks,
or a photo-curable ink that cures with ultraviolet rays. Although
the ink cartridge 8 is mounted on the carriage 6 in this
embodiment, the structure is not limited to this example. For
example, the ink cartridge 8 may be provided on a body side of the
printer 1, and the ink may be supplied to the recording head 10 via
an ink supply tube.
[0021] In a home position that is a non-printing area of the
printer 1, a wiping mechanism 11 that wipes a nozzle-formed surface
(a surface that faces the platen 3 in the recording head 10) on
which the nozzles 30 are formed in the recording head 10 is
provided. The wiping mechanism 11 includes a wiper 12 that serves
as a wiping member. The wiper 12 may be an elastic flexible member
such as rubber or elastomer. The wiping mechanism 11 sets the wiper
12 to a position where the tip end of the wiper 12 can come into
contact with the nozzle-formed surface of the recording head 10
during a wiping operation. When the wiper 12 and the nozzle-formed
surface are relatively moved with the tip end of the wiper 12 being
in contact with the nozzle-formed surface, the nozzle-formed
surface is wiped by the wiper 12.
[0022] Adjacent to the wiping mechanism 11, a capping mechanism 13
is disposed in the home position or near the home position. The
capping mechanism 13 has a cap 14 that is a sealing member that
seals the nozzle-formed surface of the recording head 10. The cap
14 is a tray-shaped member made of an elastic material such as an
elastomer and has a bottom. An upper surface of the cap 14, that
is, a surface that faces the nozzle-formed surface is open. In a
state in which the nozzle-formed surface is sealed (in a capping
state), an internal space of the cap 14 serves as a sealed space,
and the nozzles 30 are disposed within the opening of the sealed
space. To the cap 14, a pump unit 16 is connected (see FIG. 2), and
the pressure in the sealed space in the cap 14 can be reduced by an
operation of the pump unit 16. In a cleaning operation for cleaning
clogging of the nozzles 30 of the recording head 10 or an ink flow
path, when the pump unit 16 is operated to reduce the pressure in
the sealed space, the ink and air bubbles in the recording head 10
are sucked from the nozzles 30 and discharged into the sealed space
of the cap 14. When the electric power of the printer 1 is turned
off, the recording head 10 is positioned in the home position, and
a capping operation is performed to the nozzle-formed surface of
the recording head 10 by the capping mechanism 13. In an
environment in which the ink in the recording head 10 is likely to
freeze, the printer 1 according to the embodiment performs an
anti-freezing micro-vibration operation for evaporating a solvent
such as water in an ink in the recording head 10 before a capping
operation is performed in response to a power shutdown. This
processing will be described in detail below.
[0023] As illustrated in FIG. 2, the printer 1 according to the
embodiment includes a control circuit 17, a storage device 18, a
drive-signal generating circuit 19 (corresponding to a
drive-waveform generating circuit according to the embodiment), an
input and output interface 20, a button-operation reception section
22, the print-medium transport mechanism 4, the carriage-moving
mechanism 7, the wiping mechanism 11, the capping mechanism 13, the
pump unit 16, a temperature sensor 21, and the recording head
10.
[0024] The control circuit 17 is a processing device for performing
overall control of the printer and controls a printing operation
(operation of ejecting a liquid that is an original function of the
printer 1) by the recording head 10 and other operations. The
storage device 18 is a device for storing a program for the control
circuit 17 and data that is used for various control operations,
and may include a read-only memory (ROM), a random access memory
(RAM), and a nonvolatile RAM (NVRAM). The drive-signal generating
circuit 19 generates a drive signal that includes a drive pulse for
driving a piezoelectric element 31 in the recording head 10 based
on waveform data about a waveform of the drive signal. The input
and output interface 20 sends and receives various types of data,
for example, receives a request for a printing operation, print
setting information, print data, or the like from an external
device, and outputs information about a status of the printer 1 to
an external device. In this embodiment, via a wired or wireless
network, an outside air temperature (example temperature
information according to the embodiment) is obtained from weather
data or other data of the area where the printer 1 is installed.
The temperature sensor 21 detects a temperature inside the printer
1, specifically, around the recording head 10, and outputs the
detected temperature (example temperature information according to
the embodiment) to the control circuit 17. The input and output
interface 20 and the temperature sensor 21 serve as a temperature
information obtaining unit that obtains temperature information
about a temperature in the environment in which the printer 1 is
installed. The button-operation reception section 22 electrically
detects an input operation by a user through a power button (not
illustrated) that is provided on an exterior of the printer 1, and
outputs a detection signal that corresponds to the operation to the
control circuit 17. The button-operation reception section 22 may
serve as an off-operation detection unit that detects a power-off
operation and issues an instruct for turning off the electric power
of the printer 1 or an on-operation detection unit that detects a
power-on operation and issues an instruct for turning on the
electric power of the printer 1.
[0025] FIG. 3 is a cross sectional view of the recording head 10
according to the embodiment. The recording head 10 according to the
embodiment has a plurality of head components laminated and bonded
by an adhesive or the like such as a fixing plate 23, a nozzle
plate 24, a communication plate 25, an actuator unit 26, a
compliance substrate 27, and a holder 28. In the description below,
a lamination direction of the components of the recording head 10
is referred to as a vertical direction as necessary.
[0026] The actuator unit 26 according to the embodiment has a
pressure-chamber forming substrate 29, piezoelectric elements 31,
and a protection substrate 32 that are laminated as a unit. The
pressure-chamber forming substrate 29 has a plurality of pressure
chambers 33 that respectively communicate with a plurality of
nozzles 30 formed in the nozzle plate 24. Each piezoelectric
element 31 serves as a drive element that causes pressure
fluctuations in the ink in each pressure chamber 33. The protection
substrate 32 protects the pressure-chamber forming substrate 29 and
the piezoelectric elements 31. A wiring space 40 in which a
flexible circuit 39, on which a drive integrated circuit (IC) 38 is
mounted, is inserted is provided at a central portion of the
protection substrate 32. Lead electrodes of the piezoelectric
elements 31 are provided in the wiring space 40 and to the lead
electrodes, lead terminals of the flexible circuit 39 are
electrically connected. Via the flexible circuit 39, a drive signal
sent from the drive-signal generating circuit 19 is applied to the
piezoelectric elements 31. The flexible circuit 39 is not limited
to the flexible circuit 39 that has the drive IC 38; alternatively,
a flexible circuit on which the drive IC 38 is provided as a
separate component via a so-called interposer in an upper part of
the protection substrate 32 may be employed.
[0027] The pressure-chamber forming substrate 29 in the actuator
unit 26 is made of a silicon single crystal substrate. In the
pressure-chamber forming substrate 29, liquid chambers that serve
as the pressure chambers 33 are arranged in line to correspond to
the nozzles 30, forming a plurality of arrays. The pressure chamber
33 is a liquid chamber long in a direction intersecting the nozzle
arrays. An end portion of the pressure chamber 33 on one side in
the longitudinal direction communicates with a nozzle communication
port 34, and an end portion on the other side communicates with an
individual communication port 35. In the pressure-chamber forming
substrate 29 according to the embodiment, two arrays of the
pressure chambers 33 are provided.
[0028] A diaphragm 36 is laminated on an upper surface (surface
opposite to the surface on the communication plate 25 side) of the
pressure-chamber forming substrate 29. The diaphragm 36 seals an
upper opening of each pressure chamber 33. Specifically, the
diaphragm 36 defines a part of the pressure chamber 33. The
diaphragm 36 includes, for example, an elastic film composed of
silicon dioxide (SiO.sub.2) formed on the upper surface of the
pressure-chamber forming substrate 29, and an insulating film
composed of zirconium oxide (ZrO.sub.2) formed on the elastic film.
In areas corresponding to the pressure chambers 33 on the diaphragm
36, the piezoelectric elements 31 are laminated respectively.
[0029] The piezoelectric element 31 according to the embodiment is
a so-called flexure mode piezoelectric element. The piezoelectric
element 31 includes, for example, a lower electrode layer, a
piezoelectric layer, and an upper electrode layer (not shown) that
are sequentially laminated on the diaphragm 36. The piezoelectric
element 31 having such a structure bends and deforms in the
vertical direction when an electric field corresponding to the
potential difference between the electrodes is applied between the
lower electrode layer and the upper electrode layer. In this
embodiment, two arrays of piezoelectric elements 31 are provided to
correspond to the two arrays of the pressure chambers 33. The lower
electrode layers and the upper electrode layers extend from the
arrays of the piezoelectric elements 31 on both sides into the
wiring space 40 as the lead electrodes, and electrically connected
to the flexible circuit 39 as described above.
[0030] The protection substrate 32 is laminated on the diaphragm 36
so as to cover the two arrays of the piezoelectric elements 31. In
the protection substrate 32, a long accommodating space 41 capable
of accommodating the array of the piezoelectric elements 31 is
formed. The accommodating space 41 is a cavity formed from the
lower surface side of the protection substrate 32, that is, from
the diaphragm 36 side to the upper surface side, that is, toward
the holder 28 side halfway to the height direction of the
protection substrate 32. In the protection substrate 32 according
to the embodiment, the accommodating spaces 41 are formed on both
sides of the wiring space 40. To the lower surface of the actuator
unit 26, the communication plate 25 that has an area wider than
that of the actuator unit 26 is joined.
[0031] The communication plate 25 is made of a silicon single
crystal substrate similarly to the pressure-chamber forming
substrate 29. In the communication plate 25 according to the
embodiment, the nozzle communication port 34 that communicates with
the pressure chamber 33 and the nozzle 30, a reservoir 43 that is
commonly provided in each pressure chamber, and the individual
communication port 35 that communicates with the reservoir 43 and
the pressure chamber 33 are formed, for example, by anisotropic
etching. The reservoir 43 is a liquid chamber that extends along
the nozzle array direction. In the communication plate 25 according
to the embodiment, two reservoirs 43 are formed to correspond to
the nozzle arrays in the nozzle plate 24. An opening of the
reservoir 43 on a lower surface side is sealed by a compliance
sheet 44 of the compliance substrate 27. Note that a plurality of
reservoirs may be provided to one nozzle array, and inks of
different types may be provided in the respective reservoirs. The
reservoir 43 is formed by anisotropic etching from the lower
surface side of the communication plate 25. Into the reservoir 43,
an ink is introduced via an inlet 52 of an introduction liquid
chamber 51 that is provided in the holder 28 as described below. A
plurality of individual communication ports 35 are provided to
correspond to the pressure chambers 33 respectively along the
nozzle array direction. The individual communication port 35
communicates with the end portion on the other side (the side
opposite to the side where the individual communication port 35
communicates with the nozzle communication port 34) of the pressure
chamber 33 in the longitudinal direction.
[0032] In a substantially central part of the lower surface of the
communication plate 25, the nozzle plate 24 in which the nozzles 30
are formed is joined. The nozzle plate 24 according to the
embodiment is a plate that has a shape smaller than the
communication plate 25 and the actuator unit 26 and is made of a
silicon single crystal substrate. The nozzle plate 24 is bonded by
an adhesive or the like to the lower surface of the communication
plate 25 such that in an area other than the openings of the
reservoirs 43 and the nozzle communication ports 34 are open, the
nozzle communication ports 34 and the nozzles 30 communicate with
each other. In the nozzle plate 24 according to the embodiment, a
total of two nozzle arrays (nozzle groups) of the nozzles 30
arrayed in line are provided.
[0033] To the lower surface of the communication substrate 25, in
an area other than the nozzle plate 24, the compliance substrate 27
is joined. The compliance substrate 27 seals the openings of the
reservoirs 43 in the lower surface of the communication plate 25 in
a state in which the compliance substrate 27 is positioned and
joined to the lower surface of the communication plate 25. The
compliance substrate 27 according to the embodiment includes the
compliance sheet 44 and a support plate 45 that supports the
compliance sheet 44, which are joined to each other. To the lower
surface of the communication plate 25, the compliance sheet 44 of
the compliance substrate 27 is joined such that the compliance
sheet 44 is between the communication plate 25 and the support
plate 45. The compliance sheet 44 is made of a flexible thin film,
for example, a synthetic resin material such as polyphenylene
sulfide (PPS). The support plate 45 is made of a metallic material
such as stainless steel that has higher rigidity and is thicker
than the compliance sheet 44. In an area facing the reservoir 43 in
the support plate 45, a part of the support plate 45 is removed in
a shape similar to the opening in the lower surface of the
reservoir 43 to form a compliance opening 48. Accordingly, the
opening of the reservoir 43 on the lower surface side is sealed
only by the flexible compliance sheet 44. Consequently, the
compliance sheet 44 defines a part of the reservoir 43.
[0034] A portion corresponding to the compliance opening 48 in the
lower surface of the support plate 45 is sealed by the fixing plate
23. With such a structure, between the flexible area in the
compliance sheet 44 and the fixing plate 23 that faces the
compliance sheet 44, a compliance space 47 is formed. The flexible
area in the compliance sheet 44 in the compliance space 47 deforms
toward the reservoir 43 or the compliance space 47 by the pressure
fluctuations in the ink flow path, in particular, in the reservoir
43. Accordingly, the thickness of the support plate 45 is
determined based on a height required for the compliance space
47.
[0035] The holder 28 has substantially the same shape as the
communication plate 25 in a plan view. On a lower surface side of
the holder 28, an accommodating space 49 for accommodating the
actuator unit 26 is provided. The lower surface of the holder 28 is
sealed by the communication plate 25 with the actuator unit 26
being accommodated in the accommodating space 49. In a
substantially central part of the holder 28 in a plan view, an
insertion space 50 that communicates with the accommodating space
49 is open. The insertion space 50 also communicates with the
wiring space 40 in the actuator unit 26. The flexible circuit 39 is
inserted into the wiring space 40 through the insertion space 50.
In the holder 28, on both sides of the insertion space 50 and the
accommodating space 49, the introduction liquid chambers 51 that
communicate with the reservoirs 43 in the communication plate 25
respectively are provided. On an upper surface of the holder 28,
the inlets 52 that communicates with the introduction liquid
chambers 51 respectively are open. Into the introduction liquid
chamber 51, an ink sent from the ink cartridge 8 is introduced via
the inlet 52. Specifically, the ink sent from the ink cartridge 8
is introduced into the inlet 52, the introduction liquid chamber
51, and the reservoir 43, and supplied from the reservoir 43 via
the individual communication port 35 to each pressure chamber
33.
[0036] The fixing plate 23 is, for example, a metal plate of a
stainless steel. The fixing plate 23 according to the embodiment
has, in a location corresponding to the nozzle plate 24, a through
hole 23a having a shape similar to the shape of the nozzle plate 24
and a shape open in the thickness direction so as to expose the
nozzles 30 in the nozzle plate 24. As described above, the through
hole 23a communicates with a through hole opening 46 in the
compliance substrate 27. In this embodiment, the nozzle-formed
surface is defined by the lower surface of the fixing plate 23 in
the fixing plate 23 and the exposed portion of the nozzle plate 24
in the through hole 23a. The fixing plate 23 is fixed to a
supporting member such as a case (not illustrated) that supports
the recording head 10.
[0037] In the recording head 10 having the above-described
structure, in a state in which the inside of the liquid flow paths
from the introduction chambers 51 through the reservoirs 43 and the
pressure chambers 33 to the nozzles 30 are filled with an ink, when
the piezoelectric elements 31 are driven in accordance with a drive
signal from the drive IC 38, pressure fluctuations are generated in
the ink in the pressure chambers 33 and by the pressure
fluctuations, the ink is ejected from predetermined nozzles 30.
[0038] FIG. 4 illustrates example waveforms of print drive signals
to be generated by the drive-signal generating circuit 19. The
drive-signal generating circuit 19 according to the embodiment
repeatedly generates a first print drive signal COM1 and a second
print drive signal COM2 at every print unit cycle T that is defined
by a timing signal PTS and a latch signal LAT that are generated
based on scanning of the carriage 6 during a printing operation.
The print unit cycle T according to the embodiment corresponds to
one pixel of an image or the like to be printed on a print medium.
With respect to the first print drive signal COM1, the print unit
cycle T is divided into two periods T1 and T2 by a change signal
CH. In the first period T1, a micro-vibration drive pulse VP1 is
generated and in the second period T2, a first ejection drive pulse
DP1 is generated. With respect to the second print drive signal
COM2, in the print unit cycle T, a second ejection drive pulse DP2
is generated. During a printing operation, to each piezoelectric
element 31, one of the drive pulses VP1, DP1, and DP2 is
selectively applied.
[0039] FIG. 5 illustrates an example waveform of the
micro-vibration drive pulse VP1. The micro-vibration drive pulse
VP1 is a drive pulse for generating vibration (so-called micro
vibration) in the ink in the pressure chambers 33 and in the
nozzles 30 by causing pressure fluctuations in the ink in the
pressure chambers 33 to an extent that the ink is not ejected from
the nozzles 30. The micro-vibration drive pulse VP1 according to
the embodiment has an inverted trapezoidal voltage waveform and has
a first expansion element p1, a first hold element p2, and a first
contraction element p3. The first expansion element p1 is a
waveform element for decreasing a potential from a reference
potential VB to a first micro-vibration potential Vv1 that is lower
than the reference potential VB. The first hold element p2 is a
waveform element for maintaining the first micro-vibration
potential Vv1 that is a termination potential of the first
expansion element p1 for a certain period of time. The first
contraction element p3 is a waveform element for increasing a
potential from the first micro-vibration potential Vv1 to the
reference potential VB. When the micro-vibration drive pulse VP1 is
applied to the piezoelectric element 31, first, by the first
expansion element p1, the piezoelectric element 31 deforms from a
reference state (initial state) that corresponds to the reference
potential VB toward the outside (side separating from the nozzle
plate 24) of the pressure chamber 33, and the pressure chamber 33
expands from a reference volume that corresponds to the reference
potential VB to a first micro-vibration expansion volume that
corresponds to the first micro-vibration potential Vv1. The
expansion state of the pressure chamber 33 is maintained throughout
the application period of the first hold element p2. Then, by the
first contraction element p3, the piezoelectric element 31 deforms
toward the inside (a side approaching the nozzle plate 24) of the
pressure chamber 33, and the pressure chamber 33 returns from the
first micro-vibration expansion volume, which corresponds to the
first micro-vibration potential Vv1, to the reference volume. As
described above, by the expansion of the pressure chamber 33 by the
first expansion element p1 and the contraction of the pressure
chamber 33 by the first contraction element p3, pressure
fluctuations occur in the ink in the pressure chamber 33, thereby
the ink in the pressure chamber 33 and the nozzle 30 is
stirred.
[0040] The first ejection drive pulse DP1 in the first print drive
signal COM1 is a drive pulse for causing the nozzle 30 to eject ink
droplets corresponding to a smallest dot among dots that can be
formed by the printer 1 onto a print medium. The second ejection
drive pulse DP2 in the second print drive signal COM2 is a drive
pulse for causing the nozzle 30 to eject ink droplets corresponding
to a dot larger than the smallest dot. Such drive pulses are well
known, and thus the detailed description of the drive pulses is
omitted.
[0041] The micro-vibration operations performed by using the
micro-vibration drive pulses such as the micro-vibration drive
pulse VP1 can be roughly classified into two operations: a
so-called in-printing micro-vibration operation that is performed
in a print unit cycle in which ink is not ejected from the nozzle
during an operation of printing an image or the like; and a
so-called non-printing micro-vibration operation that is performed
when the electric power of the liquid ejecting apparatus is turned
on and no printing operation is performed, that is, in a standby
state. The in-printing micro-vibration operation prioritizes the
printing stability and thus reduces the overall voltage of the
micro-vibration drive pulses and reduces the inclination of
potential changes so as to reduce the residual vibration after the
micro vibration as low as possible. On the other hand, in the
non-printing micro-vibration operation, the effect of stirring is
more important than the printing stability, and thus the overall
voltage of the micro-vibration drive pulses and the inclination of
potential changes are larger than those in the in-printing
micro-vibration operation. In addition to the operations, the
micro-vibration operation includes a so-called pre-print
micro-vibration operation that is performed prior to a transition
from a standby state to a printing operation. The printer 1
according to the embodiment performs, in addition to the
above-described common micro-vibration operations, an evaporation
micro-vibration operation (vibration operation (stirring operation)
according to the embodiment) for actively evaporating a solvent
such as water in an ink from the nozzles 30 in an environment in
which the ink in the internal flow path in the recording head 10 is
likely to freeze. Hereinafter, this operation will be
described.
[0042] FIG. 6 illustrates an example waveform of a
vibration-operation drive signal COMv to be generated by the
drive-signal generating circuit 19. The drive-signal generating
circuit 19 according to the embodiment generates, in addition to
the above-described first print drive signal COM1 and the second
print drive signal COM2, the vibration-operation drive signal COMv
that is used for the evaporation micro-vibration operation. The
vibration-operation drive signal COMv is a drive signal for
generating an evaporation micro-vibration drive pulse VP2 (example
drive waveform according to the embodiment). The drive-signal
generating circuit 19 repeatedly generates the vibration-operation
drive signal COMv at every predetermined drive cycle Tv in an
evaporation micro-vibration operation.
[0043] FIG. 7 illustrates an example waveform of an evaporation
micro-vibration drive pulse VP2. In FIG. 7, the micro-vibration
drive pulse VP1 is illustrated by a broken line for comparison. The
evaporation micro-vibration drive pulse VP2 is a drive pulse for
causing pressure fluctuations in the ink in the pressure chambers
33 to the extent that the ink is not ejected from the nozzles 30
such that the ink in the pressure chambers 33 and the nozzles 30 is
vibrated and stirred to promote evaporation of a solvent such as
water in the ink in the nozzles 30. The evaporation micro-vibration
drive pulse VP2 according to the embodiment has a second expansion
element p4, a second hold element p5, and a second contraction
element p6. The second expansion element p4 is a waveform element
for reducing a potential from the reference potential VB to a
second micro-vibration potential Vv2 that is lower than the
reference potential VB and the first micro-vibration potential Vv1.
The second hold element p5 is a waveform element for maintaining
the second micro-vibration potential Vv2 that is a termination
potential of the second expansion element p4 for a certain period
of time. The second contraction element p6 is a waveform element
for increasing a potential from the second micro-vibration
potential Vv2 to the reference potential VB.
[0044] With respect to an evaporation micro-vibration drive pulse
VP2 according to the embodiment, a second micro-vibration drive
voltage (that is, a potential difference between the reference
potential VB and the second micro-vibration potential Vv2) V2 is
larger than a first micro-vibration drive voltage (that is, a
potential difference between the reference potential VB and the
first micro-vibration potential Vv1) V1 of the micro-vibration
drive pulse VP1, and inclinations (that is, potential change rates
per unit time) of the second expansion element p4 and the second
contraction element p6, which are waveform elements whose
potentials change, are larger (that is, steeper) than the
inclinations of the first expansion element p1 and the first
contraction element p3 of the micro-vibration drive pulse VP1. More
specifically, the first micro-vibration drive voltage V1 of the
micro-vibration drive pulse VP1 is set to 25% or less of a drive
voltage Vd (a potential difference between a maximum potential VH1
and a minimum potential VL1, see FIG. 4) of the first ejection
drive pulse DP1, whereas the second micro-vibration drive voltage
V2 of the evaporation micro-vibration drive pulse VP2 is set to 25%
or more and 50% or less of the drive voltage Vd of the first
ejection drive pulse DP1. The inclinations of the second expansion
element p4 and the second contraction element p6 are set as large
as possible within a range in which the ink is not ejected from the
nozzle 30. With respect to the inclinations of the second expansion
element p4 and the second contraction element p6, the range in
which the ink is not ejected from the nozzle 30 changes in
accordance with the micro-vibration drive voltage V2. Accordingly,
the inclinations of the second expansion element p4 and the second
contraction element p6 are determined in accordance with the
micro-vibration drive voltage V2 set as described above. In other
words, while the micro-vibration drive voltage V2 is maintained at
a constant voltage, a time t1 of the second expansion element p4
and a time t3 of the second contraction element p6 are determined
respectively. In the above-described example, with respect to the
first micro-vibration drive voltage V1 of the micro-vibration drive
pulse VP1 and the second micro-vibration drive voltage V2 of the
evaporation micro-vibration drive pulse VP2, the drive voltage Vd
of the first ejection drive pulse DP1 is set as a reference.
Alternatively, for example, a drive voltage of the second ejection
drove pulse DP2 may be set as a reference.
[0045] When the evaporation micro-vibration drive pulse VP2 is
applied to the piezoelectric element 31, first, by the second
expansion element p4, the piezoelectric element 31 deforms from a
reference state that corresponds to the reference potential VB
toward the outside of the pressure chamber 33, and the pressure
chamber 33 expands from a reference volume that corresponds to the
reference potential VB to a second micro-vibration expansion volume
that corresponds to the second micro-vibration potential Vv2. The
second micro-vibration expansion volume becomes larger than the
first micro-vibration expansion volume. The expansion state of the
pressure chamber 33 is maintained throughout the application period
of the second hold element p5. The application period of the second
hold element p5, that is, the time t2 is determined such that the
second contraction element p6 is applied at a timing of exciting
the vibration generated in the ink by the second expansion element
p4. Then, by the second contraction element p6, the piezoelectric
element 31 deforms toward the inside of the pressure chamber 33,
and the pressure chamber 33 returns from the second micro-vibration
expansion volume, which corresponds to the second micro-vibration
potential Vv2, to the reference volume. As described above, by the
expansion of the pressure chamber 33 by the second expansion
element p4 and the contraction of the pressure chamber 33 by the
second contraction element p6, pressure fluctuations occur in the
ink in the pressure chamber 33, thereby the ink in the pressure
chamber 33 and the nozzle 30 is stirred. The evaporation
micro-vibration drive pulse VP2 according to the embodiment has an
increased stirring effect as compared to the first micro-vibration
drive pulse VP1.
[0046] The evaporation micro-vibration drive pulse VP2 is
continuously applied multiple times to the piezoelectric element 31
in drive cycles Tv shorter than cycles in a normal micro-vibration
operation to vibrate and stir the ink, and thus a solvent such as
water in the ink is evaporated from the nozzle 30. With the
operation, the solvent evaporation starts from the vicinity of the
nozzle 30 and the ink from which some of the solvent around the
nozzle 30 has been evaporated (that is, thickened) flows toward the
pressure chamber 33 as a result of ink stirring. The repeated
evaporation micro-vibration causes the ink to be thickened from the
nozzle 30 side toward the pressure chamber 33 side. In this
operation, an application frequency fv (=1/Tv) of the evaporation
micro-vibration drive pulse VP2 is set to, for example, 20 kHz or
more and 30 kHz or less. When the application frequency fv is less
than 20 kHz, the evaporation promoting effect of the solvent such
as water in the ink decreases, whereas when the application
frequency exceeds 30 kHz, the ink is excessively stirred and the
thickening of the ink proceeds more than necessary, and thus after
the evaporation micro-vibration operation, when a next printing
operation is performed, it is difficult to recover the ejection
performance of the nozzle 30. Accordingly, the evaporation
micro-vibration operation performed within the range of the
above-described application frequencies fv enables efficient
evaporation of the solvent such as water in the ink, and thus the
ejection performance of each nozzle 30 can be recovered in a next
printing operation without problems.
[0047] FIG. 8 is a flowchart illustrating a method of controlling
the printer 1 relating the evaporation micro-vibration operation.
In a state in which the electric power of the printer 1 is turned
on, the control circuit 17 monitors the button-operation reception
section 22 and determines whether a power-off operation for issuing
an instruction for turning off the electric power of the printer 1
has been made by a user (off-operation detection process: step S1).
When no power-off operation has been detected from the
button-operation reception section 22 (No), in step S1, the control
circuit 17 continues to monitor the button-operation reception
section 22. When the power-off operation has been detected from the
button-operation reception section 22 (Yes), the control circuit 17
makes, to the user, an inquiry about information (hereinafter,
referred to as storage information as appropriate) on an
environment in which the printer 1 is installed via a printer
driver or the like executed in an external device that is connected
to the printer 1 (step S2). Specifically, the control circuit 17
urges the user to input storage information such as operating
conditions of an air conditioner in the room in which the printer 1
is placed with its electric power turned off (for example, whether
the printer 1 is placed with a heater turned on or turned off), a
period to a next turn-on of the printer 1 (hereinafter, referred to
as a shutdown period), or the like. In this operation, options
relating to the storage information may be displayed on a display
device or the like for the user to select an option from the
options.
[0048] When the control circuit 17 obtains storage information from
the user, the control circuit 17 performs temperature monitoring
(temperature information acquisition process: step S3). In the
temperature monitoring, temperature information about the
temperature in the environment in which the printer 1 is installed
is obtained. More specifically, the control circuit 17 obtains an
internal temperature (hereinafter, referred to as an apparatus
inner temperature) of the printer 1 from the temperature sensor 21
and obtains temperature information such as an outside air
temperature from the weather information of the area in which the
printer 1 is installed via the Internet or the like. The
temperature information includes predicted values of outside air
temperature changes over a predetermined period of time (for
example, the shutdown period obtained as the storage information)
from the day. Based on the storage information and the temperature
information, whether there is a possibility of ink freeze in the
internal path in the recording head 10 is determined (determination
process: step S4). In this process, for example, at the present
time (when the temperature monitoring is performed), when the ink
is not likely to freeze at the outside air temperature and the
apparatus inner temperature but there is a possibility that the
outside air temperature decreases to the freezing temperature of
the ink while the printer 1 is left under an environment in which
the heater is turned off, it is determined that there is a
possibility of ink freeze. On the other hand, even if there is a
possibility of ink freeze, if the printer 1 is stored under an
environment in which the heater is turned on, it is determined that
there is no possibility of ink freeze. The determination of the
possibility of ink freeze is performed for each ink type because
the temperature at which freeze may occur differs depending on the
ink type, that is, the composition of the ink.
[0049] Based on the storage information and the temperature
information, when it is determined that there is no possibility of
ink freeze (No), the processes in step S5 and step S6 are not
performed and the processing proceeds to the process in step S7. On
the other hand, based on the storage information and the
temperature information, when it is determined that there is a
possibility of ink freeze (Yes), the control circuit 17 performs
the evaporation micro-vibration operation (liquid vibration
process: step S5). Specifically, the control circuit 17 instructs
the carriage-moving mechanism 7 to position the recording head 10
above the capping mechanism 13 such that the nozzle-formed surface
of the recording head 10 is separated from the cap 14, and with
respect to nozzles 30 that correspond to the ink determined to have
the possibility of ink freeze, performs the evaporation
micro-vibration operation for vibrating the ink by driving the
piezoelectric elements 31 by using the evaporation micro-vibration
drive pulse VP2. As a result of the execution of the evaporation
micro-vibration vibration operation, the ink in the nozzles 30 and
the pressure chambers 33 is vibrated and stirred, and thus the
solvent such as water in the ink evaporates. Accordingly, the ink
viscosity increases.
[0050] The final amount of water in the ink by the evaporation
micro-vibration operation is adjusted based on a minimum
temperature expected based on the storage information and the
temperature information so as not to cause any failure (for
example, breakage of the components in the recording head 10 due to
expansion at the time of ink freeze) due to ink freeze inside the
nozzles 30 and the pressure chambers 33. For example, the
evaporation micro-vibration operation is performed, in a case in
which the temperature around the recording head 10 is likely to
decrease to -10.degree. C., such that the amount of water in the
ink becomes 70% or less, and in a case in which the temperature
around the recording head 10 is likely to decrease to -15.degree.
C., such that the amount of water in the ink becomes 60% or less.
The amount of water is adjusted based on the total number of
applications of the evaporation micro-vibration drive pulse VP2 to
the piezoelectric elements 31 or the execution time of the
evaporation micro-vibration operation. Since the amount of water in
less than which the ink would not freeze is different depending on
the composition of the ink or other factors, the total number of
application of the evaporation micro-vibration drive pulse VP2 or
the execution time of the evaporation micro-vibration operation is
set to a value that corresponds to the composition of the ink or
other factors.
[0051] After the evaporation micro-vibration operation has been
performed, the control circuit 17 activates the pump unit 16 to
suck and discharge the ink remaining in the cap 14 to a waste
liquid tank (not illustrated) (step S6). With this operation, the
discharging of the ink in the cap 14 before the capping operation
to the nozzle-formed surface of the recording head 10 reduces
faults due to water evaporated from the ink adhering to the cap 14
into the sealed space after the capping. Specifically, it can be
prevented that the water evaporated from the ink adhering to the
cap 14 into the sealed space after the capping mixes with the ink
in the nozzles 30, the amount of water in the nozzles 30 and the
pressure chambers 33 increases, and the ink freezes, and it can be
prevented that the water enters the space between the cap 14 and
the nozzle-formed surface and freezes. After the discharging of the
ink in the cap 14, the control circuit 17 controls the capping
mechanism 13 to perform capping by using the cap 14 to the
nozzle-formed surface of the recording head 10 (sealing process:
step S7), and turns off the electric power of the printer 1 (step
S8).
[0052] FIG. 9 is a flowchart illustrating processing to be
performed when an electric power of the printer 1 is turned on
again after the evaporation micro-vibration operation and power
shutdown of the printer 1. The control circuit 17 monitors the
button-operation reception section 22 and determines whether a
power-on operation for issuing an instruction for turning on the
electric power of the printer 1 has been made by a user
(on-operation detection process: step S10). When no power-on
operation has been detected from the button-operation reception
section 22 (No), in step S10, the control circuit 17 continues to
monitor the button-operation reception section 22. When a power-on
operation has been detected from the button-operation reception
section 22 (Yes), the control circuit 17 turns on the electric
power of the printer 1 (step S11). Then, the control circuit 17
performs an operation to discharge the ink, whose water is
evaporated and thickened by the evaporation micro-vibration
operation, from the nozzles 30 (liquid discharge process: step
S12). More specifically, in a capping state in which the
nozzle-formed surface is sealed by the cap 14, the control circuit
17 activates the pump unit 16 to discharge the thickened ink in the
nozzles 30 and the pressure chambers 33 from the nozzles 30 into
the cap 14 and discharges the ink into the waste liquid tank (not
illustrated). In this operation, the ink flow path including the
nozzles 30 and the pressure chambers 33 in the recording head 10 is
filled with a new ink from the ink cartridge 8, and thus the ink in
the nozzles 30 and the pressure chambers 33 is not replaced with
air. By the processing, the ink whose water is evaporated and
thickened by the evaporation micro-vibration operation is
discharged from the recording head 10, and the ink ejection
performance of the nozzles 30 can be recovered. Accordingly, in the
subsequent printing operation, an occurrence of a fault in the
ejection operation can be prevented. Note that the ink discharge
operation is not limited to the operation of sucking the ink from
the nozzles 30, for example, an operation of driving the
piezoelectric elements 31 to eject the ink from the nozzles 30, a
so-called flushing operation, may be employed or these operations
may be combined. When the electric power of the printer 1 is turned
off and then turned on next without the evaporation micro-vibration
operation, such a forcible ink discharge from the nozzles may be
omitted. This is because when the electric power is turned off
without the evaporation micro-vibration operation, the viscosity of
the ink in the nozzles is not increased so much and in such a case,
printing may be immediately performed.
[0053] As described above, in an environment in which ink freeze
may occur, the evaporation micro-vibration operation is performed
in response to a power-off instruction to the printer 1, and
thereby water in the ink in the ink flow path is evaporated.
Accordingly, even when the printer 1 is stored in a low temperature
environment with the electric power being actually turned off, ink
freeze in the recording head 10 can be reduced. As a result, damage
to the components of the recording head 10 due to the expansion
caused by the ink freeze can be reduced. Furthermore, no dedicated
mechanism for evaporating water in the ink is not required, and an
increase in size and complication of the apparatus can be
prevented. Furthermore, since the ink in the nozzles 30 and the
pressure chambers 33 is not replaced with air, mixing of air
bubbles in the ink can be prevented. It is not always necessary to
evaporate a solvent such as water in the entire ink, that is, to
thicken the entire ink in the pressure chambers 33. This is because
the ink in the nozzles 30 is not likely to freeze as long as water
in the ink in portions, particularly, like the nozzle plate 24,
near portions in contact with the outside air is evaporated and
thickened. Even if the ink in the pressure chambers 33 freezes and
expands, the unfrozen ink in the above portions can move in the
expanded areas (the unfrozen ink serves as a buffer material), and
thus a fault caused by freeze can be reduced. In this embodiment,
when a power-off operation has been detected and a condition in
which ink freeze may occur is satisfied based on temperature
information, the evaporation micro-vibration operation (liquid
vibration process) is performed, and thus unnecessary evaporation
micro-vibration operation can be prevented. Furthermore, the
nozzle-formed surface is sealed with the cap 14 after the
evaporation micro-vibration operation, and thereby the state in
which water in the ink is evaporated by the evaporation
micro-vibration operation can be maintained until the electric
power is turned on next. The sealing with the cap 14 reduces
excessive thickening of the ink until the electric power is turned
on next.
[0054] In the above-described first embodiment, the electric power
is turned off after the evaporation micro-vibration operation;
however when the electric power is not turned off, ink freeze in
the recording head 10 under a low temperature condition can be
reduced by sealing the nozzle-formed surface with the cap 14
without ejecting the ink from the nozzles 30 after the evaporation
micro-vibration operation. Furthermore, although an inquiry about
the storage information is made to a user when a power-off
operation has been detected in the above-described first
embodiment, the inquiry to a user may not always be performed. In
such a case, a possibility of freeze can be automatically
determined based on the temperature information that is a result of
temperature monitoring.
[0055] FIG. 10 is a flowchart illustrating a method of controlling
the printer 1 relating to an evaporation micro-vibration operation
according to another embodiment. In the above-described first
embodiment, temperature information is obtained, and a possibility
of ink freeze is determined based on the temperature information,
and then the evaporation micro-vibration operation is performed;
however, the example of the evaporation micro-vibration operation
is not limited to this example. This embodiment differs from the
above-described first embodiment in that the evaporation
micro-vibration operation is performed without obtaining
temperature information when an instruction for executing the
evaporation micro-vibration operation is issued by a user.
Specifically, in a state in which the electric power of the printer
1 is turned on, the control circuit 17 monitors the
button-operation reception section 22 and determines whether a
power-off operation for issuing an instruction for turning off the
electric power of the printer 1 has been made by a user
(off-operation detection process: step S15). When no power-off
operation has been detected from the button-operation reception
section 22 (No), in step S15, the control circuit 17 continues to
monitor the button-operation reception section 22. When a power-off
operation has been detected from the button-operation reception
section 22 (Yes), the control circuit 17 requests to the user an
instruction to perform or not to perform the evaporation
micro-vibration operation via a printer driver or the like executed
in an external device that is connected to the printer 1
(instruction request process: step S16). More specifically, the
printer 1 requests the user to determine whether there is a
possibility of ink freeze in a state in which the electric power is
turned off, and receives from the user an instruction to perform or
not to perform the evaporation micro-vibration operation based on
the determination. In this process, options corresponding to the
determination of executing the evaporation micro-vibration
operation and the determination of not executing the evaporation
micro-vibration operation may be displayed on a display device or
the like for the user to select an option from the options.
[0056] Then, whether an instruction from the user is an instruction
for executing the evaporation micro-vibration operation or not is
determined (step S17). When the instruction from the user is an
instruction for not executing the evaporation micro-vibration
operation (No), the processes in step S18 and step S19 are not
performed, and the processing proceeds to the process in step S20.
On the other hand, when the instruction from the user is an
instruction for executing the evaporation micro-vibration operation
(Yes), the control circuit 17 executes the evaporation
micro-vibration operation similarly to the above-described first
embodiment (liquid vibration process: step S18). The execution of
the evaporation micro-vibration operation vibrates and stirs the
ink in the nozzles 30 and the pressure chambers 33 and thus water
in the ink evaporates. The processes in steps S19 to S21 are
similar to those in steps S6 to S8 in the first exemplary
embodiment, and accordingly, the descriptions of the processes are
omitted.
[0057] In this embodiment, similarly to the above-described first
embodiment, even when the printer 1 is stored in a low temperature
environment in a state in which the electric power is turned off,
ink freeze in the recording head 10 can be reduced. As a result,
damage to the components of the recording head 10 due to expansion
caused by the ink freeze can be reduced. In this embodiment, when
an execution instruction is issued by a user, the evaporation
micro-vibration operation is performed, and thus unnecessary
evaporation micro-vibration operation can be prevented.
[0058] Although a so-called flexible vibration piezoelectric
element 31 has been exemplified as a drive element in the
above-described embodiment, embodiments are not limited thereto.
For example, a so-called longitudinal vibration piezoelectric
element may be employed. Furthermore, the drive element is not
limited to the piezoelectric element; alternatively, the drive
element may be a drive element that can vibrate and stir a liquid
in the pressure chamber and the nozzle, such as an electrostatic
actuator, a heat generation element, or the like.
[0059] In the above-described embodiments, as the drive waveforms
used for the evaporation micro-vibration operation, in addition to
the micro-vibration drive pulse VP1 that is used for a normal
micro-vibration operation such as the in-printing micro-vibration
operation, the dedicated evaporation micro-vibration drive pulse
VP2 is used; however, the drive waveforms are not limited thereto.
For example, the micro-vibration drive pulse VP1 that is used for a
normal micro-vibration operation may be used as the evaporation
micro-vibration operation drive pulse for the evaporation
micro-vibration operation. In such a case, the application
frequency of the micro-vibration drive pulse VP1 for the
piezoelectric element 31 in the evaporation micro-vibration
operation may be set to an appropriate frequency for further
efficient evaporation of the solvent in the ink. Furthermore, as
the vibration drive waveform used for the evaporation
micro-vibration operation, a waveform in which a potential change
direction, that is, the vertical direction (polarity) is reversed
from that of the example evaporation micro-vibration drive pulse
VP2 may be employed. In the above-described embodiments, when the
evaporation micro-vibration operation (liquid vibration process:
step S5 or S18) is performed in the method (flowchart illustrated
in FIG. 8 or FIG. 10) of controlling the printer 1 relating to the
evaporation micro-vibration operation, the information that
indicates that the evaporation micro-vibration operation has been
performed may be stored in the storage device 18. In such a case,
in the process (flowchart illustrated in FIG. 9) that is performed
after the evaporation micro-vibration operation, turning off the
electric power of the printer 1, and turning on the electric power
next, after turning on the electric power of the printer 1 (step
S11), whether the information indicating that the evaporation
micro-vibration operation has been performed is stored in the
storage device 18 is determined. When the information indicating
that the evaporation micro-vibration vibration operation has been
performed is not stored in the storage device 18, the process may
be ended without performing the operation (liquid discharge
process: step S12) of discharging the ink, whose water has been
evaporated and thickened by the evaporation micro-vibration
operation, from the nozzles 30. On the other hand, when the
information indicating that the evaporation micro-vibration
operation has been performed is stored in the storage device 18,
the operation to discharge the ink, whose water is evaporated and
thickened by the evaporation micro-vibration operation, from the
nozzles 30 (liquid discharge process: step S12) is performed, the
information indicating that the evaporation micro-vibration has
been performed is deleted from the storage device 18, and the
process may be ended. Furthermore, when a time from an execution of
the evaporation micro-vibration operation and a power-off operation
(step S8 or S21) to a next power-on operation is measured and the
information indicating that the evaporation micro-vibration has
been performed is not stored in the storage device 18, if the
measured time is greater than or equal to a predetermined period,
the liquid discharge process (step S12) may be performed. When a
time from an execution of the evaporation micro-vibration operation
and a power-off operation (step S8 or S21) to a next power-on
operation is measured and the information indicating that the
evaporation micro-vibration has been performed is stored in the
storage device 18, the power for discharging the thickened ink in
the nozzles 30 and the pressure chambers 33 into the cap 14 in the
liquid discharge process (step S12), that is, the suction force,
the operation time, or the like may be increased as the measured
time becomes longer.
[0060] Although the recording head 10, which is an example liquid
ejecting head, has been described in the above-drescribed
embodiments, embodiments of the disclosure are applicable to other
liquid ejecting heads having components that may be damaged by
liquid freeze and liquid ejecting apparatuses having the liquid
ejecting heads. For example, embodiments of the disclosure may be
applicable to liquid ejecting heads each having a plurality of
color material ejecting heads to be used to manufacture color
filters for liquid crystal displays or the like, electrode material
ejecting heads to be used to form electrodes for organic electro
luminescence (EL) displays, field emission displays (FEDs), or the
like, or bioorganic substance ejecting heads to be used to
manufacture biochips (biochemical elements), or may be applicable
to liquid ejecting apparatuses having any of these heads.
* * * * *